1. Field of the Invention
The invention relates to a device for removing oil or oil-containing substances from a foreign liquid, in particular water, with a system for collecting the oil.
2. The Prior Art
Such devices are known in many different forms and are mainly used for cleaning oil-contaminated waters or seas. A major part of the known plants operates according to the suction principle, with exploitation of the knowledge that oil is lighter than water and floats on the surface of water. Before the oil is drawn off the surface of the water by suction, so-called oil barriers, for example in the form of inflatable hoses are put into place with most of the conventional plants, within which barriers the oil can be collected on the surface of the water. Furthermore, an oil-collecting ship has been built in the meantime, which is divided in two halves in the direction of travel, which halves are connected with one another in the stern zone via a joint. For removing the oil by suction, the two halves are folded apart and then serve as a collection barrier for the oil. Said oil-collecting ship is currently operating under the name "Mellum".
However, it has been found that the known plants have only a relatively low collection capacity and that they, therefore, do not operate very efficiently. They are thus usable only for cleaning locally contaminated water, thus waters with a relatively small contaminated area. For cleaning larger waters or even seas such as, for example the currently oil-contaminated Persian Golf, the known plants and devices are overtaxed because the cleaning would take months to years in such cases. Furthermore, the known plants and devices are quite complicated in their structure and thus susceptible to maintenance.
Also, chemical cleaning of oil-contaminated water has been proposed on various occasions. In connection with one of said processes, chemical additives are added to the water for the purpose of bonding the oil. However, in such a case, the chemical additives bonding the oil must then be removed, which is no less problematic than the direct removal of the oil. Another problem is that a major part of the chemical binding agents is not compatible with the environment as well.